Re: [PATCH 4/4] pata_platform: Use 16-bit wide data transfer

[Tejun Heo <tj@kernel.org>]

Hello,

On Sat, Aug 23, 2014 at 02:46:12PM +0400, Alexander Shiyan wrote:
> In some cases, system bus can be configured for 16-bit mode, in this
> case using of read/write functions for the 32 bit values causes two
> cycles of 16 bits, which is incorrect.

Shouldn't we distinguish them instead of forcing 16bit transfer on
all?

> The patch provides its own function to use the proper 16-bit mode.
> 
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> ---
>  drivers/ata/pata_platform.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ata/pata_platform.c b/drivers/ata/pata_platform.c
> index ecbc3bf..79dd223 100644
> --- a/drivers/ata/pata_platform.c
> +++ b/drivers/ata/pata_platform.c
> @@ -43,13 +43,28 @@ static int pata_platform_set_mode(struct ata_link *link, struct ata_device **unu
>  	return 0;
>  }
>  
> +static unsigned int pata_platform_xfer_noirq(struct ata_device *dev,
> +					     unsigned char *buf,
> +					     unsigned int buflen, int rw)
> +{
> +	unsigned long flags;
> +	unsigned int consumed;
> +
> +	local_irq_save(flags);
> +	/* Use 16-bit transfer */
> +	consumed = ata_sff_data_xfer(dev, buf, buflen, rw);
> +	local_irq_restore(flags);
> +
> +	return consumed;
> +}

This doesn't seem like a good location for this function.  Please
rename the existing noirq function to xfer32_noriq and add generic
xfer_noirq for 16bit xfers.

Thanks.

-- 
tejun